Before bed, I write down only how much I studied today.

Under the covers, I write down how long I studied today, and what I learned starts to blur.

Scenes

I wrote down my study time, but... — Under the covers, I write down how long I studied today. The number stays, but I can’t quite remember what I learned.
I counted the time, but the page didn’t stay with me. — Writing down how much I studied, like thirty minutes or an hour, shows how long I spent studying. It doesn’t tell me what I learned.
I can’t see where to begin tomorrow. — When I record only the time, it’s hard to find the next problem to solve or concept to review when I look back at my notes. So I hesitate again at the first page.
Try writing down just one thing you learned. — Try writing what you studied today in one line. If you got stuck somewhere, note that too, so you can see where to pick up tomorrow.
Notes don’t change overnight either. — Even after writing one line, you may still feel unsure where to begin the next day. When that happens, take another look at whether the words in your notes point to a clear starting place.